The present invention relates to a storage box disposed at substantially the upper central portion of a body frame of a motorcycle and provided with improved elements associated with the storage box.
In a general structure of a motorcycle, an engine unit is mounted below main tubes which are extended to the rear portion from a head pipe, and a seat is placed on seat rails which are extended further rearward from the rear end of the main tubes. A layout may be adopted, if it is necessary to provide a storage box which is capable of containing a large article such as helmet, that the storage box is positioned above the main tubes by relocating a fuel tank to a place such as under the seat.
The storage box is provided with an upper opening for introducing articles to be stored, and a lid is attached hereto. The lid is upwardly rotated or swung by a hinge mechanism for opening and closing the lid and is locked by a lock mechanism for locking it in a closed position. The hinge mechanism and the lock mechanism are disposed in the storage box body in a preferred arrangement, but it is desired, if possible, that they be small in size so as not to cause a reduction in the storage box volume.
On the other hand, there is a demand for a high functional capability which improves the operability in opening and closing the lid. For example, the following features are desired: provision of a spring to lighten the lid opening and closing force, easy locking and unlocking for the lock mechanism with the stable locked position, and a feasibility of manual unlocking at the time of a battery failure if it is electromagnetically operated while providing a security against a theft, for example, resulting in a problem that an increase in size and thickness is unavoidable if these demands are to be satisfied.
In another aspect, a seal member is interposed between the storage box and the lid to seal the interior so that rain or washing liquid does not enter thereinto at the closed position of the lid. To seal the opening of a storage box of this type, for a configuration where a seat is used instead of a movable cover, in a conventional arrangement, a rib raised at the peripheral edge of the opening is covered by a bead-like seal member so that a seat bottom is brought into contact thereto in a resilient manner. In a case of using a lid, an inner flange is formed on the lower edge portion of the lid so that the seal member contacts thereto in a resilient manner. However, if the lid has a shape as described above, a slide metallic mold is required, in the case of forming with plastics, for an undercut portion to be formed above the flange, making it disadvantageous from the standpoint of productivity and costs. In addition, a shrinkage cavity tends to occur on a surface at the portion from which the flange is raised, damaging the outer appearance, thus creating a problem for the sealing of the lid for the storage box equipment.
In a further aspect, the lid made of a synthetic resin thin plate does not have a sufficient rigidity and tends to be easily deformed. For reasons such as the outer appearance, the lid is usually attached so that the inner peripheral edge of the lower end thereof is brought into contact with the outer peripheral edge of the opening, whereby a gap is easily caused due to an outward deformation. Particularly, since a person's hand may easily be inserted into the storage box by forcibly pulling the side surface portion which may be most easily deformed, there is a fear that the stored articles may be stolen. Although improving the rigidity of the lid material to prevent this problem may be considered, it is difficult to achieve in terms of costs, weight or contained volume.
In a still further aspect, regarding the lock mechanism, a variety of mechanisms may be employed as the locking method thereof. The lock mechanism may be operated by a single switch and be readily operated by combining it with the key cylinder of the engine switch, resulting in the advantage of structural simplification. With an electromagnetic method, however, the unlocking may become impossible due to a failure in the electrical system, whereby a mechanical provision for an emergency unlocking system is necessary. Furthermore, it is required that the emergency unlocking system itself is also provided with an anti-theft function such as by means of a seat lock operation or a lock mechanism which cannot be operated in an unauthorized manner. In such case, if a large-sized device is to be added, a problem occurs that the advantage of the electromagnetic unlocking operation is significantly reduced.